Scanning probe-based lithography method

Abstract

A resist medium in which features are lithographically produced by scanning a surface of the medium with an AFM probe positioned in contact therewith. The resist medium comprises a substrate; and a polymer resist layer within which features are produced by mechanical action of the probe. The polymer contains thermally reversible crosslinkages. Also disclosed are methods that generally includes scanning a surface of the polymer resist layer with an AFM probe positioned in contact with the resist layer, wherein heating the probe and a squashing-type mechanical action of the probe produces features in the layer by thermally reversing the crosslinkages.

The invention claimed is: 
     
       1. A method, comprising:
 removing a portion of a polymer resist layer comprising Diels-Alder adducts to reveal an alignment marker, wherein the polymer resist layer contains thermally reversible crosslinkages; 
 aligning an AFM probe with the alignment marker; and 
 scanning a surface of the polymer resist layer with the AFM probe positioned in contact with the resist layer to thermo-mechanically reverse the crosslinkages and produce features in the layer. 
 
     
     
       2. A method as claimed in  claim 1 , wherein thermo-mechanically reversing the crosslinkages comprises heating the AFM probe to a temperature greater than 140° C. 
     
     
       3. A method as claimed in  claim 1 , wherein the thermally reversible crosslinkages are covalent bonds. 
     
     
       4. A method as claimed in  claim 1 , wherein the thermally reversible crosslinkages are Diels-Alder adducts. 
     
     
       5. A method as claimed in  claim 1 , wherein the Diels-Alder adduct is the product of a dienophile and a substituted furan. 
     
     
       6. A method as claimed in  claim 1 , wherein the thermally reversible crosslinkages are non-covalent bonds. 
     
     
       7. A method as claimed in  claim 6 , wherein the non-covalent bonds are hydrogen bonds. 
     
     
       8. A method as claimed in  claim 1 , wherein the polymer resist is a silicone derivative. 
     
     
       9. A process for producing features in a resist medium, comprising:
 arranging a heat-emitting probe that is connected to a resistive path, so that the probe is in contact with a resist medium that includes a substrate and a polymer resist layer comprising Diels-Alder adducts within which features are produced by thermo-mechanical action of the probe, wherein the polymer resist contains thermally reversible crosslinkages; and 
 driving a current through the resistive path to heat the probe to a feature-forming temperature, thereby causing local softening of the polymer resist layer and allowing an AFM probe to penetrate the resist layer to form an indentation; and 
 removing an area of the resist medium with the probe to expose alignment marks on the substrate, thereby permitting the probe and the substrate to be aligned prior to further lithographic processing. 
 
     
     
       10. A process as claimed in  claim 9 , for producing a pattern of two-dimensional shapes made by drawing primitives selected from lines and pixels. 
     
     
       11. A process for reading the topography of a resist medium patterned by a process as claimed in  claim 9 , wherein the resistive path is mechanically coupled to a tip placed in contact with the resist medium, comprising:
 driving a current through the resistive path and determining the thermal conductance between the medium and the resistive path. 
 
     
     
       12. A process for reading the topography of a resist medium patterned by a process as claimed in  claim 9 , comprising:
 placing a tip in contact with the resist medium; and 
 operating a position sensor for measuring a vertical position of the tip with respect to a reference plane in the resist medium.